Altered respiratory control in newborn puppies after chronic prenatal exposure to alpha-1-acetylmethadol (LAAM).
Respiratory studies were conducted on newborn puppies chronically exposed to alpha-l-acetylmethadol . HCl (LAAM) during portions of gestation. Bitches received daily oral doses of LAAM from the second week through the sixth week of pregnancy (LAAM-6) or through the end of a 9-week pregnancy (LAAM-9), but not after parturition. LAAM-9 pups displayed narcotic abstinence signs during the first week after birth, while LAAM-6 pups did not. LAAM-9 pups had increased tidal volume, respiratory frequency, alveolar ventilation and O2-consumption and decreased alveolar CO2-tension during the first week of life compared to placebo-treated controls. The LAAM-9 CO2-response curve was significantly displaced to the left of control. These data are consistent with relative hyperventilation during neonatal withdrawal from LAAM. LAAM-6 pups had decreased tidal volume and alveolar ventilation during 4 of the 6 weeks studied. These changes in ventilation were associated with a decrease in O2 consumption. By 6 weeks after birth CO2-response curves of both LAAM-9 and LAAM-6 pups were shifted to the right of control. These changes in CO2-responsiveness suggest the possibility of prolonged disturbances of respiratory control which may continue beyond the sixth week of life.
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D002245:Carbon Dioxide / Q000494:pharmacology; D002697:Chloral Hydrate / Q000494:pharmacology; D004285:Dogs; D005260:Female; D006801:Humans; D008691:Methadone / Q000031:analogs & derivatives*; D008692:Methadyl Acetate / Q000494:pharmacology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012119:Respiration / Q000187:drug effects*; D012890:Sleep / Q000187:drug effects / Q000502:physiology; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology; D013997:Time Factors
D002245:Carbon Dioxide; D002697:Chloral Hydrate; D008692:Methadyl Acetate; D008691:Methadone